From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,5a97e6705e234408 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-09-26 08:19:43 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!canoe.uoregon.edu!hammer.uoregon.edu!skates!not-for-mail From: Stephen Leake Newsgroups: comp.lang.ada Subject: Re: Expected bytes per sloc (semicolons) performance Date: 26 Sep 2001 11:19:24 -0400 Organization: NASA Goddard Space Flight Center Message-ID: References: <9oqrgf$jc3$1@nh.pace.co.uk> NNTP-Posting-Host: anarres.gsfc.nasa.gov Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: skates.gsfc.nasa.gov 1001517643 9805 128.183.220.71 (26 Sep 2001 15:20:43 GMT) X-Complaints-To: dscoggin@cne-odin.gsfc.nasa.gov NNTP-Posting-Date: 26 Sep 2001 15:20:43 GMT User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 Xref: archiver1.google.com comp.lang.ada:13402 Date: 2001-09-26T15:20:43+00:00 List-Id: "Marin David Condic" writes: > > > It does raise an interesting problem. If you have to commit to certain > parameters early on in the project (such as memory or processor speed) how > do you estimate how much you'll need when you don't have the software yet? Exactly. Pretending this problem doesn't exist is _not_ an acceptable solution. > Even assuming you've got prior experience with similar systems, you > really have no good basis in measurement to make estimates until > there is some actual software available. Maybe this suggests that > software development should start way in advance of hardware > decisions. Exactly. That's what "phase A"/prototypes are for. You can't commit significant resources to a project until you know what you are doing. > But that has its own problems with respect to time-to-market and > other considerations. Well, building satellites for NASA is certainly different than getting out the next cell phone. But I think the same principles apply; you have to experiment and prototype before you commit the final design. > Everyone can criticize just about any attempt to make measurements > and estimates for lots of good reasons. Who could suggest a better > alternative for how to make these estimates early on in a project > when critical decisions must be made? I did just that; get a similar processor or simulator, write some prototype code. Or, agree that you will only make evolutionary changes from the previous release. That's really the same thing; the previous release is a good prototype. -- -- Stephe